The general power receptacles are fixed receptacles because they are usually mounted on walls or partitions or arranged within furniture. In addition, the common extension cord receptacles are also fixed receptacles. As known, the positions of the insertion holes of the fixed receptacles are fixed and fail to be changed. Since the positions of the insertion holes are fixed, the plug can only be inserted to receptacle in specified directions. In some situations, the power cord that is connected to the plug needs to be bent. If the power receptacle has been used for a long term, the power cord is readily detached or fractured. Moreover, when a plug of a large-size connector (e.g. a linear adapter) is inserted into the fixed receptacle, the neighboring fixed receptacle is usually hindered by the large-size connector because the width of such connector is larger than the distance between two adjacent fixed receptacles.